Bag closure



April 3, .1945. v BRADY 2,373,010

BAG CLOSURE Fil ed May 25, 1942 FIGIQ Patented Apr. 3, 1945 UNITEDSTATES PATENT OFFICE .(lharles V. Brady, Webster Groves, Mo... or

to Bcrnis Bro. Bag corration of 1.

@ompamy, St. llrouls, Me, a

Application 3 23, 1942, Serial No. dddfldd d llla.

This invention relates tobag closures, and with regardto certain morespecific features to clo sures for bags which are to contain hygroscopicor like materials.

Among the several objects of the inventionmay be noted the provision ofa moisture-proofing seal in and around needle-holes, which under alltemperature conditions avoids a sticw or tacky characteristic on the bagexterior although the sealing material retains the usual tacky orlikecharacteristics which go with a desired permanent flexibility in theclosure; the provision of a seal of the class described in which optimumplacement and distribution of sealing material is obtained for moreeffective sealing in and around is often intended that this, of hascontain material which should be kept dry d which may take up moisture(is hygroscopic) these bags heretofore have had their taped and sewnends dipped into a low melting point was which substantially covered theoutside of the tape and the stitched thread. This was intended to enterthe needle holes from the outside, thus to plug the holes against entryof moisture.

This procedure has had several disadvantages,

the first of which was that in the of a clo-,

' sure for a filled the bag needed to be turned the needle holes; andthe provision of a seal of' this class which is simple and economical tocarry out in practice, Other objects will be in part obvious and in partpointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter described. and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of variouspossible embodiments of the Similar referencecharacters indicatecorresponding parts throughout the several views of the drawing.

It has been common practice to close bags, in-

cluding paper bags by bringing together-the opposite sides of the bagmouth, app a V: shaped covering tape, and sewing through the opfilling,and for bag tops, atterfilllng. This operation has involved punchingneedle holes through the tape and through the has material, which holesalthough partially filled with thread or twine, are not hygroscopicallytight. Since it posite sides of the tape and bag. For bag bot-- toms,the operation has been performed prior to upside down in order to applythe wax, since spraying or brushing was not satisfactory. sides, theclipping was dimcult, and particularly so with heavy materals and largebs. The contained materials tended to deform the h end when the bag wasinverted and made more cult a dipping operation.

Another disadvantage of the former method was that the war: only enteredthe needle holes superficially from the outside, and in addition thetacky wax was located on the outside of the bag ends where subsequentlyit caused culties'.

The present invention avoids all of the above troubles and produces amuch more water-tight seal throughout the whole interior of the closure.Referring now more particularly to Fig 1, there is shown at numeral i afour-ply, gusseted bag, but it is to be understood that the invention isequally applicable to non= and single-ply bags, both oi the tubular and.l varieties. and also to valved bass.

The front and rear sides or t of the bag are shown at t and t. Theii-shaped coverin tape is shown generally at l, the same ha oppositesides t and ii folded tow one another and enclosing the mouth. itsindicated in Fig. 4, where bags have alr been filled, it is the practiceto brine together the ends of the faces g and t, the filled bag being ona movable belt I beneath a running supply of the tam l which is turnedinto a V- which, in conjunction with the w the sewing machine, draw thee through the sewing machine. It is to be imde 1 r that after passingthrough the draw rolls it the continuous sewn mm is out between When theclosure forms a bottom, the bag is of course flat when the closure is e,which is necessarily prior to filling.

Prior to fillin The successive filled bass are brought or covering withtape and sewing, each bag, according to the present invention, has itsopen end dipped into melted, low

melting point wax, the results of which on a multi-ply bag are indicatedin Fig. 2. The dipping is carried out, for example, to a depth of aboutone inch into the wax. that is to say, beyond the point at which thesewing is to take place. At room temperature, the wax solidifies butretains enough tackiness to flex with the bag material. Sewing isordinarily accomplished at a distance of about five-eighths tothree-quarters of an inch from the end of the bag. As indicated in Fig.2, the wax under these conditions is deposited on both faces of the bagmouth and also on all faces and inter faces of each ply. Thus all facesof all plies are provided with a wax surface or coating which at roomtemperature, before sewing, solidifies more or less. without becominghard. The wax is shown-by stippled-dots in the drawing, and is providedwith the index character 23. It may be composed, for example, of paramn,thinned with enough petrolatum to maintain tackiness or stickiness andto prevent cracking upon solidification. The temperature for melting toa flowing liquid may be around 150 F.

Either or both ends of the bag may be treated as above indicated, andthe tape is then sewn on, but in the case of the top, the bag is fil edprior to applying the tape.

Assuming that we are dealing with a bag top. the bag is filled afterdipping and hardening but before applying tape if. It is then advancedtoward the sewing machine I? and the supply of tape i. The opposite endsoi? the faces 5 and '43 are suitably brought together by hand. asindicated at the right in Fig. i. The tape 9, which in the presentexample is made of paper, is then folded in the folder '5 and appliedover the bag end. The assembly then proceeds to the sewing machine 971.It is to he understood that the folded tape is not covered with wax, butis dry paper so that the presser foot of the sewing machine I? operateson a. dry surface. How ever, the presser foot squeezes the wax inside ofthe tape. The needle 2? of the sewing machine reciprocates through theopposite sides of the tape 9 and through the bag plies, including thewax, and performs its sewing operation as usual.

The dry tape strips clean the needle as it recip rocates.

The proper operation of the stitching is not interfered with, becausethe wax is not in a running condition. being more or less solidifiedthough tacky at ordinary room temperatures.

After leaving the sewingmachine H, the sewn tape is subjected to heat,as indicated by the infra red lamps 29, which serve again to melt e waxso that it proceeds to infill the needle hol s aro1md the thread passingthrough said holes, thus sealing them from the inside. In addition, thesqueezing draw (rolls l9 may be kept warm by means of additional lamps31. The squeezing action of these rolls 19, as also the squeezing of thepresser foot at Il aids in forcing the wax into sealing position. Eitheror both sets of lamps 29 or 3| may be made to provide the heating step,or other heating means may be used. The heat should only be enough tomelt the wax without damaging the bag or tape material, such as paper orwaterproof fabric.

It is to be understood that when the invention is applied to providing asimilar closure at the other end of the bag to form its bottom, the

bottom closure is made prior to filling the bag on suitable machineryfor the purpose.

From the above, it will be seen that, instead of a superficial closureof the needle holes, there is an interior closure or plugging of thesame. In addition, instead of a large area. of wax being exposed on theexterior of the bag, none is exposed because the exterior surface of thecover tape 1 has no wax on it, and the exterior loops of the threadentirely cover the outer ends of the needle holes, substantiallypreventing outfiow of wax. Thus the bag mouths are exteriorly dry, evenwhen warmed, and they do not tend to stick to adjacent bags or articles.In addition, the appearance of the bag is much neater, since there is nodipping mark of wax on the exterior.

The distribution of wax is much better because it flows inside andoutside of the bag plies as well as between the piles, and thereforemakes a better distribution for eflective sealing.

It will be seen that dipping is the best manner of applying thesubstance to the bag end, particularly in the case of a 'multiply paperbag wherein the dipping operation at once covers all oi the faces andinter faces at the ply ends. In the case of gusseted bags, thedistribution of material into the gussets is also made easier toaccomplish by dipping. For example, it is difficult to brush or spraymaterial between plies or in gussets. However, some of the advantages ofthe invention may be obtained by applying the wax by other methods whenthis is effective and possible, as for example on non-gusseted,single-ply bag bottoms.

The invention is most useful in the case of paper bags, or bags linedwith treated paper or similar waterproofing. substances. Paper is aclass example of materials which protect against -m0isture when properlytreated. Thus, if the bags are made of cloth suitably treated to closethe interstitial spaces, such bags could advantathat the substance towhich it applies may be made liquid at a. temperature low enough that abag treated therewith will not w deteriorated by the temperaturerequired for melting. Wax is exemplary of any material which is properlyamorphous, waterproof and of low melting point. The intention is tocover broadly sealing materials which retain their properties of sealingagainst moisture when located upon a flexible base such as thematerialof the bag, cover tape, and stitching. Low melting point asphaltwould be an exemplary equivalent for wax for certain uses.

The term tubular bag" as used herein is intended to cover bags having(broadly) tubular bodies whether seamed. unseamed, gusseted, multiply,valved, or not, unless otherwise qualified.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in A the accompanyingdrawing shall be interpreted ingpoint flexible sealing substancecovering all iaces and inter i'aces or said plies near the bee oi theinto low melting point flexible sealing substance in such a mannerthat'the faces and inter faces of the multi-ply portions are entirelycovered tor a predetermined distance from said ends, allowing saidsubstance to solidify, bringing the bag ends adjacent to one another,applying an enclosing cover tape over the bag end, said tape being freeof adhesive prior to application to the bag end. the width of the tapeon each side being such as to cover the entire treated area, stitchingthrough the tape and the bag end within said area while the substance issolid, and

' thereafter heating the bag through the tape to render said substancetemporarily liquid interiorly to plug the holes caused by sewingsubstantially without exuding to the outside of the tape.

3. 4 bag closure comprising adiacently located bag end portions, a layerof low melting point sealing substance covering the outer laces andinteriaces of said end portions, a v-shaped cover tape encl said has endand a thereto by the sealing was on the outside 0! the outer laces.stitching passing through the tape and said bag end portions. the holesformed by said stitching in the bag end portions beins completelypenetrated from two sides and sealed by said substance, but the holesthrough the tape being merely backed by said substance withoutsubstantial penetration to the exterior, whereby a closure is providedwith all internal stitching openings completely closed from two sides bythe sealing substance which is substantially confined to locationsinside the tape, the outside oi the tape being substantially free ofsaid sealing substance.

4. A bag closure comprising adiacently located multi-ply bag endportions, a layer of low melting point fusible sealing substancecovering adjacent bands on all faces and inter-faces of said plies. av-shaped cover tape enclosing said bag end and attached thereto by thesealing substance on the outside of the outer plies, stitching passingthrough the tape and said bag end, the holes in all plies formed by saidstitching being completely penetrated from two sides and sealed by saidsubstance, but the holes through the tape being merely backed by saidsubstance without substantial penetration to the etxerior, whereby aclosure is provided with allinternal stitching openings completelyclosed from two sides by the sealing substance which is substantiallyconfined to locations inside the tape, the outside of the tape beingsubstantially tree oi said sealing substance.

CHARLES V. BRADY. v

